The present invention relates generally to the detection and ejection of foreign matter from crop harvesting machines and, more particularly, to a latch mechanism which can be actuated by either electronic or mechanical foreign matter detection devices to release a trap door for ejection of the foreign matter from the flow of crop being harvested.
Generally, crop harvesting machines, commonly referred to as combines, include a crop harvesting header mounted at the forward end thereof to initiate the crop harvesting process. Normally, the harvested crop is consolidated within the header and fed to a centrally located conveying mechanism within a feeder housing. From the feeder housing the harvested crop is fed to the combine base unit for further harvesting treatment.
It has been found desirable to eliminate non-crop foreign matter from the flow of harvested crop before it reaches the base unit for further harvesting treatment. Foreign matter includes stones, wood and other debris and such can be harmful to the harvesting equipment normally housed within the base unit. Combines utilizing the rotary harvesting principal are particularly susceptible to damage from such non-crop foreign matter.
Accordingly, non-crop foreign matter detection devices, commonly referred to as stone traps, have been developed. One such mechanical detection device utilizes a pinch roller mounted above the flow of crop material through the feeder housing a predetermined distance above a trap door. Non-compressible matter, such as stones, entering the crop flow between the pinch roller and the trap door and having a height greater than the distance between the roller and trap door, is forced downwardly against the trap door to force the trap door open and eject the foreign matter. Electronic detection devices have also been developed for sensing the presence of such matter and emitting a signal receivable by an ejection mechanism to remove the foreign matter from the flow of crop.
To provide a more successful detection rate of non-crop foreign matter, a combine could include both an electronic and mechanical detection device. It would be advantageous for a combine utilizing both detection devices to utilize a common ejection mechanism, e.g. a trap door, and latching mechanisms.